Concrete tamping device



June 9, 1936. F. A KERWIN CONCRETE TAMPING DEVICE Filed July 2e,

1935 2 Sheets-Sheet l INVENTOR l?. @nM/'7 ATTORNEYS June 9, 1936.

CONCRETE TAMPING DEVICE VFiled July 26, 1933 P. A. KERWIN 2 Sheets-Sheet2 ATTORNEYS Patented June 9, 1936 UNITED STATES CONCRETE TAMPING DEVICEPhilip A. Kerwin, Detroit, Mich., assigner to City of Detroit,Department of Street Railways,

Wayne County, Mich.

Application July 26, 1933, Serial No. 682,196

5 Claims.

The present invention pertains to a novel machine for tamping concreteand the primary object is to provide means for distributing or placingfreshly poured concrete between tracks of a street railway as a uniformconsistently dense mass in full contact with the under surfaces of thetracks and in full contact with all exposed surfaces of the ties andplates that support the same.

Another object of the present invention is to provide a machine fortamping freshly poured concrete without causing segregation of theconcrete mass by settling the heavier parts thereof, and thus provide auniformly dense concrete mass that is free from voids or air pockets andwhich is placed in all crevices and angles of reinforcing members orother devices to be imbedded in the concrete.

Various means and methods have heretofore been used in order to improvethe density of freshly poured concrete and in order to cause theconcrete mass to be placed beneath the tracks of a street railway andthe ties that support the same and in analogous concrete constructionWork where steel members are to be imbedded in the concrete, the chiefamong prior attempts being in the form of means for vibrating the railsor other steel members and thus transmitting vibration to the concrete.With this method the heavier aggregate forming the concrete was causedto settle, and a lighter formation adjacent the under side of the railsor adjacent th-e steel or other imbedded members resulted in a poor orweak support for the rails or other imbedded member after the concretehardened. Furthermore when stopping operations at night and blocking theconcrete as is the usual custom, the concrete thus poured becomes partlyset, or is in green condition by the time operations are resumed thenext morning, which makes it impossible to vibrate the rails or otherimbedded members that extend outwardly from the green concrete into thefreshly poured concrete which is a continuation of that poured thedaybefore because that vibration is not only transmitted to the freshlypoured concrete, but to the green concrete also and destroys the bearingor support beneath the rails and ties, or other imbedded members, and itdestroys the bond between the concrete and the rails or other imbeddedmembers, which causes a pocket to form adjacent the steel imbeddedmembers which when exposed to the weather becomes filled with water withharmful results. In using a device for vibrating the rails, the samecannot be usedexceptwhen it is sufliciently far away from green concreteas to avoid possibility of the vibration reaching the green concrete. Itis, therefore, another object of the present invention to provide amachine that may be used to tamp, distribute and place concrete that ispoured closely adjacent green concrete without injuring the latter.

Still another object of the present invention is to provide means fortamping freshly poured concrete between tracks of a street railway,without imparting vibration or shocks to the tracks or ties in a mannerto destroy their proper alignment, elevation or spacing, or in a mannerto loosen spike fastened tracks in cases where wood ties are used.

With the above and other ends in view the invention consists in mattershereinafter set forth and more particularly pointed out in the appendedclaims, reference being had to the accompanying drawings, in whichFigure `1` is a top plan view of the present tamping machine;

l'ig.` 2 is an end elevation;

Fig. 3 is a side elevation;

Fig. 4 is a vertical cross section;

Figs. 5 and 6 are elevations of other forms of tampers. v

Like characters of reference are employed throughout to designatecorresponding parts.

The numeral I designates a vehicle frame or chassis having bearings 2secured to the underside thereof adjacent opposite ends, the bearingsbeing provided to rotatably support the front axle 3 and the rear axle4. Rubber pads 2 are preferably interposed between the bearings and theframe so that any vibration that is set up on the frame as a result ofthe operation of mechanism to be described will not be transmitted fromthe frame to the wheels. 0n the axles 3 and 4 are mounted wheels 5 whichare illustrated as having guide flanges that make them suitable fortraversing rails or tracks 6. The tracks 6 represent any conventional orwell known railway construction and it will be understood that they maybe secured in parallel alignment by metallic ties 6 and supportingplates 62 such as illustrated or theymay be secured to wood ties byspikes. It will be understood, although the preferred embodiment of thisinvention relates particularly to the problem of placing concreterelative to railway tracks, that the present device is adaptable forplacing concrete construction work, and that it is not con-V fined tothis use alone.

Supported by the chassis I are .vertical guide members 'I within whichis slidably mounted a carriage 8 which includes a top plate 9, a bottomplate I0, and I-beams I I for securing said plates in spaced relation ina manner to resist any torsional stress that might be imparted to thecarriage 8 by any external forces. Mounted on the plate 9 are pairs ofsheaves I2, each pair of sheaves being mounted adjacent opposite ends ofthe carriage,` and each sheave in each pair being mounted adjacent thesides of the carriage. A cable I3 is trained under each pair of sheavesI2 and each cable has one end anchored as at I4-A in one guide member 'Iwith its other end secured to a shaft I5 that is mounted in a guidemember I on the opposite side of the carriage. The shaft I5 is equippedwith a hand wheely I6 so that the same may be manually rotated in orderto Wind the cables I3 around the same and thus cause said cables toraise the carriage 8, or unwind said cables so that the force ofgravi-ty causes said carriage B to move downwardly.

Bearings II are mounted in each of the plates 9 and I0 and supportshafts I8 sol that the same may bereciprocated in a manner to bedescribed. Ony the lower ends of the shafts I8 are mounted cylindricaltampers I9 having their lower ends rounded as at 2l) to eliminateVsuction when the same are forced into contact with freshly pouredconcrete, and to exert a pushing action against the concretelin alldirections corresponding to radii of the rounded bottom thereof. A horizontally extending shaft 2|. is supported in bearings 22 above theplatev 9 of the carriage and is rotated through a belt 23 by an electricmotor 24 that is also mounted on the plate 9f. The shaft 2I is providedwith eccentrics 25 upon which are mounted bearings 26 of connecting rods21 that are pivotallyl connected as at 28 to the shafts I8.

From the foregoing it becomes apparent that the shaft 2| is caused to;rotate by the motor 24 and rotation of the eccentrics as an-integralpart of the shaft causes reciprocal movement ofthe connecting rods 21,and thus. cause'reciprocation of the shafts I8 and of the tampers I9. Byrotating, the hand Wheel I6' the shaft I-5 maybe rotated to unwind thecables I3 therefrom and permit the carriage to lo-weruntil the tampers Il-l-extend` beneath the surface of freshly poured plastic concrete 29 asillustrated inl Fig. 4.

The `cams 25, as shown are illustrativer only, and could not be drawn toproper scaleA because their throw is relatively small, and thereforewhen the tampers are projected beneath the surface of concrete aggregatethe electric motor rotates the eccentricsso: as to provide a rapidsuccession of op-V posed movements of the tampers While the same are;imbedded within thel plastic mass. 'In this Ina-nner the softmass isinitially displaced downwardly when the` tampers move below the surface,andas the tampers move upwardly the material tendsfto move back, butrapidity of the tamper movementV prevents such replacement takingplace,A and as a result a series of tamping impulses are made effectivelaterally by a. tendency to displace any material that'might have movedback beneath the tamper during upward movement thereof.

In order to provide for movement of the entire: mechanism longitudinallyalongy the tracks E there is provided a stub shaft 30' that is supinported directly above the axle 4 in a bearing 3|, the` shaft having ahand wheel' 32 on one end that facilitates manual rotation thereof, anda sprocket 33 on its other end that is'connected by a chain 34 to asprocket 35 on the axle 4. Thus by manually rotating the hand wheel 32the axle 4 and wheels 5 thereon may be caused to rotate.

Referring to Fig. 2 where the present device is illustrated in one stageof the concrete distributing and placement operation, it will be notedthat the freshly poured concrete 29 is rst poured between the tracks 6and the action of the tampers I9 resulting from their verticalreciprocation is to force or push the concrete under the cross membersor ties 6 and under the plates 62 so that it comes up and falls inContact with the outside surfaces of the rails 6 and on top of theportions of the ties 5 and plates 62 which extend outside the rails asdesignated generally at 36. It will be noted that the tampers at no timecontact with the rail and that while the concrete is in plastic formthev pushing action of the tampers does not cause vibration to betransmitted through the concrete to the rails.

In 5 therey is illustrated a tamper head 31 having` a conical bottom 38which when reciprocated in aconcrete mass tends to displace the samelaterally, rather than downwardly and in Fig. 6 there is illustrated atamper head having a semi-spherical bottom 39, which when reciprocatedin a, concrete mass tends to displace the material in radial directions.

Although a specific embodiment of the present invention has beenillustrated and described it is to be understood that various` changesmay be made in the details of construction without departing from thespirit of the invention as set forth in the appended claims, and suchchanges are contemplated.

WhatI claim is:

l. The combination. with a wheeledv truck, of a vertically movablecarriage supported therein, a shaft rotatably supported by said carriageand having a plurality of eccentri'cs thereon, a plurality of verticallyreciprocable shafts mounted in said carriage, tampers mounted on thelower ends of' said plurality of shafts, connecting rods individuallyconnecting the upper ends of the shafts to said eccentrics, saideccentrics having a comparatively small throw whereby they impart arelatively short stroke to said connecting rods, means for rotating saideccentric bearing shaft at a high rate of speed whereby to reciprocatesaid tampers at a comparatively high rate, and means for moving saidYcarriage to position said tampers with respect to wet concrete wherebysaid tampers remain beneath the surface of said wet concrete during saidreciprocations.

2. The combination with a wheeled truck, of a vertically movablecarriage supported therein, a shaft rotatably supported by said carriageand having a plurality of eccentrics thereon, a plurality of verticallyreciprocable shafts mounted in said carriage, tampers mounted on thelower ends of said plurality of shafts, connecting rods individuallyconnecting the upper ends of the shafts to said eccentrics, saideccentrics having a comparatively small throw whereby they impart arelatively short stroke to said connecting rods, means for rotating saideccentric bearing shaft at a high rate of speed whereby to reciprocatesaid tampers at a comparatively high rate of speed, vibration absorbingmeans between said carriage and the Wheels on said truck, and means formoving said carriage to position said tampers with respect to wetconcrete whereby said tampers remain beneath the surface of said wetconcrete during said reciprocations.

3. The combination with a wheeled truck, of

vertical guides, a carriage slidable in said guides, tampers mounted forreciprocal movement in said carriage, means on said carriage forreciprocating said tampers whereby the stroke thereof is comparativelyshort, means for operating said reciprocating means at a comparativelyhigh rate of speed, and means for moving said carriage with respect towet concrete whereby said tampers remain beneath the surface of said Wetconcrete during said reciprocations.

4. The combination with a Wheeled truck, of a vertically movablecarriage supported therein, a shaft rotatably supported in said carriageand having a plurality of comparatively small throw eccentrics thereon,means for rotating said shaft at a comparatively high rate of speed,connecting rods individually connected to said eccentrics, tamper heads,and vertically reciprocable shafts mounted in said carriage andindividually connecting said connecting rods to said tamper heads, saideccentrics being adapted to impart comparatively high speed andcomparatively short reciprocations to said tampers, and said verticalshafts being adapted to support said tampers with respect to wetconcrete whereby the tampers remain beneath the surface of said Wetconcrete during said reoiprocations.

5. The combination with a wheeled truck, of a vertically movablecarriage supported therein, a shaft rotatably supported in said carriageand having a plurality of comparatively small throw eccentrics thereon,means for rotating said shaft ata comparatively high rate of speed,connecting rods individually connected to said eccentrics, tamper heads,bearings Xedly positioned in said carriage, and vertically reciprocableshafts mounted in said bearings and individually connecting saidconnecting rods to said tamper heads, said eccentrics being adapted toimpart comparatively high speed and comparatively short reciprocationsto said tampers, and said vertical shafts being adapted to support saidtampers with respect to wet concrete whereby the tampers remain beneaththe surface of said Wet concrete during said reciprocations.

PHILIP A. KERWIN.

